U.S. patent application number 15/113946 was filed with the patent office on 2016-11-24 for powder improvement for additive manufacturing.
This patent application is currently assigned to United Technologies Corporation. The applicant listed for this patent is UNITED TECHNOLOGIES CORPORATION. Invention is credited to Zizzis A. Dardas, Ying She.
Application Number | 20160339521 15/113946 |
Document ID | / |
Family ID | 53681843 |
Filed Date | 2016-11-24 |
United States Patent
Application |
20160339521 |
Kind Code |
A1 |
Dardas; Zizzis A. ; et
al. |
November 24, 2016 |
POWDER IMPROVEMENT FOR ADDITIVE MANUFACTURING
Abstract
A method includes providing a metallic first powder having a
plurality of first particles with a first mean particle diameter. A
second powder added to the first powder has a plurality of second
particles with a second mean particle diameter less than the first
mean particle diameter. Energy is applied to at least the second
powder so as to selectively heat the second particles. The first
powder is combined with the heated second powder to form a modified
powder including modified powder particles. Modified powder
particles have an interior portion containing an interior
composition, and an outer surface portion with an outer composition
different from the interior composition.
Inventors: |
Dardas; Zizzis A.;
(Worcester, MA) ; She; Ying; (East Hartford,
CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UNITED TECHNOLOGIES CORPORATION |
Hartford |
CT |
US |
|
|
Assignee: |
United Technologies
Corporation
Hartford
CT
|
Family ID: |
53681843 |
Appl. No.: |
15/113946 |
Filed: |
January 12, 2015 |
PCT Filed: |
January 12, 2015 |
PCT NO: |
PCT/US2015/011059 |
371 Date: |
July 25, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61931295 |
Jan 24, 2014 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B22F 7/008 20130101;
B23K 15/0086 20130101; B22F 1/0014 20130101; B22F 3/1055 20130101;
B22F 2301/052 20130101; B33Y 70/00 20141201; Y02P 10/295 20151101;
B23K 26/0006 20130101; Y02P 10/25 20151101; B22F 2302/105 20130101;
B22F 2302/20 20130101; B22F 2301/20 20130101; B33Y 10/00 20141201;
B29C 64/153 20170801; B22F 2998/10 20130101; B23K 26/342 20151001;
B22F 1/02 20130101; B22F 2301/15 20130101; B22F 2301/205 20130101;
B23K 15/0093 20130101; C23C 24/04 20130101 |
International
Class: |
B22F 3/105 20060101
B22F003/105; B22F 1/02 20060101 B22F001/02; B23K 15/00 20060101
B23K015/00; B22F 7/00 20060101 B22F007/00; B23K 26/342 20060101
B23K026/342; B33Y 10/00 20060101 B33Y010/00; B33Y 70/00 20060101
B33Y070/00; B22F 1/00 20060101 B22F001/00; B23K 26/00 20060101
B23K026/00 |
Claims
1. A method comprising: providing a metallic first powder having a
plurality of first particles with a first mean particle diameter;
adding a second powder to the first powder, the second powder
having a plurality of second particles with a second mean particle
diameter less than the first mean particle diameter; applying
energy to at least the second powder so as to selectively heat the
second particles; and combining the first powder with the heated
second powder to form a modified powder including modified powder
particles having an interior portion containing an interior
composition, and an outer surface portion with an outer composition
different from the interior composition.
2. The method of claim 1, wherein the interior composition is
substantially identical to a composition of the first powder.
3. The method of claim 1, wherein the outer composition is
substantially identical to a composition of the heated second
powder.
4. The method of claim 1, wherein the outer composition includes at
least some of the second powder alloyed with a portion of the first
powder.
5. The method of claim 1, wherein the first powder comprises a
metal selected from a group consisting of: nickel, titanium,
chromium, aluminum, and alloys thereof.
6. The method of claim 1, wherein the second powder comprises a
second metallic material or a precursor thereof.
7. The method of claim 6, wherein the second metallic material is
an alloying element compatible with the first metallic
material.
8. The method of claim 1, wherein the second powder comprises a
ceramic material or a precursor thereof.
9. The method of claim 8, wherein the second material comprises a
ceramic material selected from a group consisting of: boron
nitride, silicon carbide, silicon nitride and combinations
thereof.
10. The method of claim 1, further comprising: consolidating the
modified powder into at least part of a bulk material.
11. The method of claim 10, wherein the consolidating step
comprises: disposing the combined first powder and second powder
onto a working surface of an additive manufacturing apparatus; and
operating an energy beam in a linear manner so as consolidate the
combined powders into at least one layer of a bulk material.
12. The method of claim 10, wherein the consolidating step
comprises: placing the combined first powder and second powder into
a feed chamber of a cold spray apparatus; and operating the cold
spray apparatus to form a coating on a bulk material.
13. A method for operating an additive manufacturing apparatus, the
method comprising: providing a metallic first powder material
having a mean diameter of more than about 500 nm to a working
surface of the additive manufacturing apparatus; adding a second
powder material to the working surface, the second powder material
having a mean diameter of less than about 100 nm; directing an
energy beam to apply energy to at least the second powder material
so as to selectively heat the second particles; and combining the
first powder with the heated second powder to form a modified
powder including modified powder particles having an interior
portion containing an interior composition, and an outer surface
portion with an outer composition different from the interior
composition.
14. The method of claim 13, wherein the metallic first powder
comprises a metal selected from a group consisting of: nickel,
titanium, chromium, aluminum, and alloys thereof.
15. The method of claim 13, wherein the second powder comprises a
second metallic material or a precursor thereof.
16. The method of claim 13, wherein the second powder comprises a
ceramic material.
17. The method of claim 16, wherein the second material comprises a
ceramic material selected from a group consisting of: boron
nitride, silicon carbide, silicon nitride, and combinations
thereof.
18. A method for forming at least part of a bulk material with a
cold spray apparatus, the method comprising: providing a metallic
first powder having a plurality of first particles with a first
mean particle diameter; adding a second powder to the first powder,
the second powder having a plurality of second particles with a
second mean particle diameter less than the first mean particle
diameter; applying energy to at least the second powder so as to
selectively heat the second particles; combining the first powder
with the heated second powder to form a modified powder including
modified powder particles having an interior portion containing an
interior composition, and an outer surface portion with an outer
composition different from the interior composition; accelerating
the modified powder particles through the cold spray apparatus; and
directing the accelerated powder particles toward a substrate.
19. The method of claim 18, wherein the metallic first powder
comprises a metal selected from a group consisting of: nickel,
titanium, chromium, aluminum, and alloys thereof.
20. The method of claim 18, wherein the second powder comprises a
second metallic material.
21. The method of claim 20, wherein the second metallic material
comprises at least one alloying composition compatible with the
first metallic material.
22. The method of claim 18, wherein the second powder comprises a
ceramic material.
23. The method of claim 22, wherein the second material comprises a
ceramic material selected from a group consisting of: boron
nitride, silicon carbide, silicon nitride and combinations thereof.
Description
BACKGROUND
[0001] The described subject matter relates generally to powder
metallurgy, and more specifically to additive manufacturing
employing metal powders.
[0002] Current approaches for additive manufacturing (AM) processes
employing metal powders (Cold Spray, DMLS, etc.) use the powder
either as received or degassed (typically under vacuum or inert
gas) or passivated (usually by surface oxidation). In these cases,
the best mechanical properties which can be obtained are those of
the base material, presuming that all surface contamination,
adsorbed moisture and hydroxides have been successfully removed or
play a negligible effect to these properties. Processes to remove
surface moisture and hydroxides from metal powders have been
already disclosed. The desire to produce parts from metal powders
by AM processes having enhanced mechanical properties, at least
equal or better than those of the baseline powder, still
remains.
SUMMARY
[0003] A method includes providing a metallic first powder having a
plurality of first particles with a first mean particle diameter. A
second powder added to the first powder has a plurality of second
particles with a second mean particle diameter less than the first
mean particle diameter. Energy is applied to at least the second
powder so as to selectively heat the second particles. The first
powder is combined with the heated second powder to form a modified
powder including modified powder particles. Modified powder
particles have an interior portion containing an interior
composition, and an outer surface portion with an outer composition
different from the interior composition.
[0004] A method for operating an additive manufacturing apparatus
includes providing a metallic first powder material having a mean
diameter of more than about 500 nm to a working surface of the
additive manufacturing apparatus. A second powder material is added
to the working surface which has a mean diameter of less than about
100 nm. An energy beam is directed to apply energy to at least the
second powder material so as to selectively heat the second
particles. The first powder is combined with the heated second
powder to form a modified powder including modified powder
particles. The modified particles have an interior portion
containing an interior composition, and an outer surface portion
with an outer composition different from the interior
composition.
[0005] A method for manufacturing a bulk material includes
providing a metallic first powder having a plurality of first
particles with a first mean particle diameter. A second powder
added to the first powder has a plurality of second particles with
a second mean particle diameter less than the first mean particle
diameter. Energy is applied to at least the second powder so as to
selectively heat the second particles. The first powder is combined
with the heated second powder to form a modified powder including
modified powder particles. Modified powder particles have an
interior portion containing an interior composition, and an outer
surface portion with an outer composition different from the
interior composition. The modified powder particles are accelerated
through a cold spray apparatus, and are directed toward a
substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 shows modification of a powder for use in making at
least part of a bulk material.
[0007] FIG. 2 is an example process chart for making a modified
powder as illustrated in FIG. 1.
[0008] FIG. 3 schematically depicts an example additive
manufacturing apparatus for using a modified powder.
[0009] FIG. 4 shows an example cold spray apparatus for using a
modified powder.
DETAILED DESCRIPTION
[0010] The best properties of a bulk material produced by additive
manufacturing, assuming removal of surface contamination, porosity,
and moisture, are limited, particularly during production when
certain other properties may be desirable to facilitate a
particular process such as additive manufacturing or spraying.
Applying a surface treatment to particles allows for improved
manufacturing while retaining many or all of the desired bulk
material properties.
[0011] FIG. 1 shows provided first particles 12 of metallic first
powder material 10 having first mean diameter d.sub.1, and second
particles 16 of second powder material 18 having a second mean
diameter d.sub.2, in which d.sub.2 is generally less than first
mean diameter d.sub.1.
[0012] Particles 12 of first powder material 10 are generally
intended for use, for example in an additive manufacturing process
to form a bulk material, or can be applied either by additive
manufacturing or by a spray to form a coating for a bulk material.
However, the bulk properties of first powder material 10 formed
from first particles 12 are generally limited by the bulk
composition. For example, first powder material 10 may have a
composition suitable for forming a thermal barrier coating onto a
substrate. However, first particles 12 may be have a hardness which
is too high to facilitate efficient spraying (due lack of plastic
deformation) without undue loss of material. In other cases, it can
be difficult for first powder material 12 to penetrate or
agglomerate together about first particle perimeters 14. This may
be due to relatively low thermal conductivity or other issues which
increase energy consumption during production. Thus it would be
helpful to improve certain surface properties of first particles 12
without substituting or changing the composition (and resulting
properties) of the bulk material.
[0013] To alter outer surface properties of first particles 12,
second particles 16 of second powder material 18 can be introduced
in various process environments. Second powder material 18 can, for
example, be a second composition (or a precursor thereof) which can
operate as an outer layer or surface layer for particles 10 prior
to or during consolidation.
[0014] Energy can then be applied to at least some of second powder
material 18 so as to selectively melt second particles 16 of second
powder material 18 while leaving at least internal portions 20 of
first particles 12 unmelted. Energy can be applied in various forms
and will be discussed with respect to illustrative examples.
[0015] In certain embodiments, only perimeters 14 of many first
particles 12 are molten. First powder material 10 can be combined
with melted second powder 18 such that particles 24 of modified
powder 22 can include parts of first particles 12 of metallic first
powder 10 coated with outer layer 26. Outer layer 26 can be either
melted second powder material 18, or a new altered or alloyed
composition. Second particles 16 will thus generally introduce a
particular property to the outside of modified particles 24, which
have improved handling of as compared to first particles 12 during
a bulk manufacturing or consolidation process. In certain
embodiments, second powder material 18 can be a ceramic composition
or an alloying composition (or a precursor thereof), which is
broken down during other steps of the process. Examples of such
approaches will be discussed in turn.
[0016] FIG. 2 shows a method for making a bulk material from a
metallic powder. Certain steps of method 100 are illustrated in
FIG. 1. Method 100 includes step 102 in which first particles of a
first powder are provided, followed by step 104, where second
particles of a second powder are added to the first powder.
Generally speaking, a mean particle diameter of the first particles
is greater than a mean particle diameter of the second particles to
facilitate the combination of materials and to ensure that the bulk
properties are not unduly compromised by the addition or alteration
of the outer surface layer. In certain embodiments, the first
particles can have a mean diameter of more than about 500 nm, while
the second particles, additionally and/or alternatively, can have a
mean diameter of less than about 100 nm The nanoscale second
particles provide effective mixing of particles and even coverage
of the larger first particles during later steps in which the
particle surface is modified.
[0017] In step 106, energy is added to at least the second powder
so as to selectively heat the second particles. At least some of
the second particles are then converted into a partial or complete
molten state so that they can help form an outer surface of the
modified particles. In certain embodiments, the second particles
are actually precursor compositions, and break down into an
alloying element or a protective composition upon the application
of sufficient energy.
[0018] Next, in step 108, the first powder and the heated second
powder are combined to form a modified powder. As briefly described
with respect to FIG. 1, there are two general ways that the second
particles can modify surface properties of the first particles.
First, upon contact, some of the melted second powder can be
alloyed with partially melted outer surfaces of the first powder
particles. After they are solidified, the composition of the outer
surface layer contains an alloy of the first powder and at least
one constituent of the second powder. Alternatively, the second
particles solidify about perimeters of the first particles to form
its own outer surface layer on the modified particles, while
substantially maintaining the same composition on the interior
portion of the modified particle. Whether the melted second powder
forms an alloy or a separate outer surface layer on particles of
the first powder will depend on the choice of materials and the
relative phase relationships and system energy.
[0019] In one example, the first powder can be a metallic material
(or precursor) selected from a group consisting of: nickel,
titanium, chromium, aluminum, and alloys thereof.
[0020] The second powder can include at least a second metallic
material, or metal precursor(s). In the case where the second
material is metallic, the second material (or resulting
composition) will typically include at least one alloying element
compatible with the composition making up the outer portion of the
first particles. This combination provides a surface alloy which
can help facilitate deposition and/or bonding of the first powder
as a bulk material, while ensuring that many of the resulting bulk
material properties are maintained based on the substantially
identical interior portion of the modified particles. To further
minimize effects on the bulk material, the alloying element can be
selected to be inert to one or more properties of the bulk material
in small concentrations.
[0021] In another example, the second powder can include a ceramic
material (or precursor). Nonlimiting examples include boron
nitride, silicon carbide, silicon nitride and combinations thereof.
In this case, the ceramic (or precursor) generally does not
directly interact with the composition of the first powder, and
instead results in a protective coating disposed about the metallic
first particles.
[0022] After forming the modified particles (step 108), step 110
includes consolidating the modified particles (i.e., a combined
first powder and second powder) to form at least part of a bulk
material.
[0023] In one instance, step 110 includes consolidating the
modified particles via an additive manufacturing apparatus.
Generally, the modified particles can be disposed onto a working
surface of the additive manufacturing apparatus. For example, the
modified particles can be formed separately, and prior to their
introduction to the apparatus. Alternatively, combining step 108
can be done at or immediately prior to the time of their
introduction onto the working surface in step 110. An illustrative
example of this process is shown with respect to FIG. 3.
[0024] Regardless of whether the particles are combined separately
from or with the additive manufacturing process, step 110 can
include operating an energy beam in a linear manner so as
consolidate the combined powders into one or more layers of a bulk
material, followed by solidifying the modified powder. In
alternative embodiments, step 110 can include placing the modified
particles (combined first powder and second powder) into a feed
chamber of a cold spray apparatus. A cold spray apparatus can then
be operated to apply a coating to, and/or build a bulk material
using the modified particles. This example is best seen in FIG.
4.
[0025] FIG. 3 schematically illustrates operation of additive
manufacturing apparatus 200 to form at least part of a bulk
material, and in which the modified particles are incorporated to
make the bulk material. FIG. 3 shows only one non-limiting example
of a powder bed type additive manufacturing process and apparatus,
and is not meant to limit the described subject matter to a single
process or machine Embodiments of apparatus 200 utilize various
additive manufacturing processes, such as but not limited to direct
metal laser sintering (DMLS) manufacturing or Selective Laser
Sintering (SLS) manufacturing, direct laser melting (DLM)
manufacturing, selective laser melting (SLM) manufacturing, laser
engineering net shaping (LENS) manufacturing, electron beam melting
(EBM) manufacturing, direct metal deposition (DMD) manufacturing,
and others known in the art.
[0026] Build table 210 includes movable build platform 216, which
can be any object which is capable of being mounted to additive
manufacturing apparatus 200 for building one or more near-net shape
components. Powder delivery system 218 is capable of supplying
successive quantities of metal powder to build platform 216. In
this example, powder delivery system 218 includes powder
compartment 220 with powder elevator platform 222 disposed
proximate to, and movable opposite build platform 216. Build arrows
224 indicate that powder elevator platform 222 is movable in a
first vertical direction, and build platform 216 is movable in a
second vertical direction opposite the first vertical direction.
However, it will be appreciated that other powder supply
arrangements can be used such as those where the metal powder is
injected into an energy beam before it reaches the intended working
surface(s).
[0027] In the example shown in FIG. 3, operation of apparatus 200
can begin with providing metallic first powder material 10 to a
working surface (e.g., movable build platform 216) of additive
manufacturing apparatus 200. Second powder material 18 can be added
to the working surface as well via powder injector 223 or other
suitable device for combining first and second powder materials 10,
18 proximate build platform 216.
[0028] FIG. 3 shows a non-limiting example of energy beam apparatus
226 with beam generator 228 and outlet lens 230 adapted to steer
energy beam 232 generally along beam path 234 toward build platform
216. This example is simplified for brevity, and it will therefore
be understood that other more complex electron or laser beam
configurations (e.g., steering mirrors, prisms, and/or multi-axis
CNC systems) can be incorporated to operate other embodiments of
energy beam apparatus 226.
[0029] After applying energy to combined first powder and second
powder materials 10, 18 with energy beam 232 to selectively melt
particles of second powder material 18 (and optionally outer
particle surfaces of first powder material 10), the combined powder
materials 10, 18 include interior portions 20 of the metallic first
powder coated with outer surface layers 26 (shown in FIG. 1). In an
additive manufacturing environment, the outer surface layer may
remain in a partially or completely molten state to facilitate
consolidation of the powder into a bulk material. However, it will
be appreciated that, in certain embodiments, a first (typically low
power) pass can be made with energy beam apparatus 226, prior to a
higher power pass used to consolidate first and second powders 10,
18 into modified powder 22 (as shown in FIG. 1).
[0030] As noted above with respect to FIGS. 1 and 2, first and
second powder materials 10, 18 can alternatively be combined into
modified powder 22 prior to their provision to the working surface.
In this case, modified powder 22, which may be produced by a
fluidized bed process, is provided directly to powder compartment
220 in place of first powder material 10 and subsequently moved
over onto build table 216. As such, the steps of combining the
particles and adding energy can be performed by the incorporated
fluidized bed apparatus rather than additive manufacturing
apparatus 200.
[0031] FIG. 3 also shows powder bed build plate 236 disposed on
build platform 216 to serve as a substantial portion of an initial
working surface for build assembly 240. A plurality of successively
deposited powder build layers are provided from powder supply 242
by recoater 244 to build assembly 240. Each powder build layer can
then be converted into successively formed component build layers
according to a computer model, which can be stored in an STL memory
file or other electronic data file accessible by a controller (not
shown) of additive manufacturing apparatus 200. Selective areas of
each successive deposited layer can be sintered or otherwise
adhered to the preceding layer by energy beam 232. After each
successive layer, recoater 244 is returned to a starting position
near elevator platform 222, while supply piston 246 advances upward
to expose another layer from powder supply 242, while build
platform 216 indexes down by approximately one layer thickness. The
process is repeated until build assembly 240 is complete with one
or more near-net shape components built in a layerwise manner.
Generally, each successive iteration of first and second deposition
surface(s) comprise at least a portion of a preceding build layer
250. There may be some overhang and discontinuities, depending on
the final build requirements and the capabilities of the build
apparatus.
[0032] In another example, FIG. 4 schematically illustrates
operation of cold spray apparatus 300 in which modified powder 22
can be utilized to produce at least part of a bulk component, such
as in a protective coating. "Cold spray" generally refers to a
class of processes also known as "cold gas dynamic spraying". Cold
spray processes can be used either to coat a workpiece, and/or to
form a bulk component over a mandrel having a shape corresponding
to the desired shape of the bulk workpiece.
[0033] FIG. 4 shows substrate 310, which can be a workpiece or
mandrel as described above. Surface 312 receives particles of
modified powder 22 which have been accelerated into one or more
streams 314 exiting nozzle 316 of spray gun 318. Particles of
modified powder 22 can be accelerated into stream 314 using one or
more pressurized inert gases such as N.sub.2 and/or He as shown in
FIG. 4. Prior to their introduction into the feed chamber, at least
some of the first and second particles can be combined into
modified particles 322 using a fluidized bed process. This process
is described in detail in commonly assigned application Ser. No.
61/815,359, filed on Apr. 24, 2013, and the entirety of which is
hereby incorporated by reference.
[0034] To facilitate spraying, first powder 10 and second powder 18
are combined to form modified powder 22 in a manner such as is
shown and described with respect to FIGS. 1 and 2. Returning to
FIG. 4, particles of modified powder 22 are fed from a hopper,
chamber or other suitable powder feed device 320 through one or
more feed lines 322. Modified powder can be carried through feed
line(s) 322 via carrier gas. After being accelerated through nozzle
316, stream(s) 314 of modified powder 22 are deposited onto
workpiece surface 312.
[0035] Cold spray process have traditionally required a limited
size range of particles. Particles which are too large can distort
any previously deposited materials, while smaller particles lack
the momentum to penetrate a bow shock layer around surface 312.
Modified particles 24 can be tailored according to embodiments of
this process so that outer surface layer 26 (shown in FIG. 1) has
increased or decreased hardness (relative to the underlying
material). This can allow a different (e.g., wider or more
cost-effective) range of particle sizes can efficiently be utilized
with cold spray apparatus 300.
[0036] In one illustrative, but non-limiting example, substrate 310
is an airfoiled workpiece intended to be installed into a turbine
engine. Turbine airfoils are often provided with various
environmental and thermal barrier coatings to extend their useful
lives under harsh operating conditions. The hardness of coatings
prevents damage and penetration of foreign objects, heat, and
contaminants. This hardness is also reflected in the coating
particles themselves. Thus under current techniques, when some
types coating particles are sprayed toward the blades, a number of
compositions are too hard to effectively and efficiently be sprayed
onto the desired location on the substrate, causing uneven coating
application and lost particles.
[0037] In part of this example, first powder 10 (shown in FIG. 1)
can include particles of a thermal barrier composition with a
Vickers hardness of at least 800. Second particles 18 can include a
boron precursor such as diborane. Prior to introduction into cold
spray apparatus 300, boron derived from second particles 18 can be
alloyed with the outer surface of the first particles (originating
with a TBC composition), and forms a softer outer particle layer
which helps modified powder 22 absorb the momentum imparted by
spray gun 318 upon contact with another surface. By absorbing more
momentum, modified powder 24 is gradually slowed as it reaches
substrate 310. This causes less waste of large particles and can
result in a more uniform coating. Smaller particles can also be
modified with a harder outer surface to help penetrate the bow
shock layer (not shown) about substrate 310.
DISCUSSION OF POSSIBLE EMBODIMENTS
[0038] The following are non-exclusive descriptions of possible
embodiments of the present invention.
[0039] A method for manufacturing a component includes providing a
metallic first powder having a plurality of first particles with a
first mean particle diameter. A second powder added to the first
powder has a plurality of second particles with a second mean
particle diameter less than the first mean particle diameter.
Energy is applied to at least the second powder so as to
selectively heat the second particles. The first powder is combined
with the heated second powder to form a modified powder including
modified powder particles. Modified powder particles have an
interior portion containing an interior composition, and an outer
surface portion with an outer composition different from the
interior composition.
[0040] The method of the preceding paragraph can optionally
include, additionally and/or alternatively, any one or more of the
following features, configurations and/or additional
components:
[0041] A method for manufacturing a component according to an
exemplary embodiment of this disclosure, among other possible
things includes providing a metallic first powder having a
plurality of first particles with a first mean particle diameter;
adding a second powder to the first powder, the second powder
having a plurality of second particles with a second mean particle
diameter less than the first mean particle diameter; applying
energy to at least the second powder so as to selectively heat the
second particles; and combining the first powder with the heated
second powder to form a modified powder including modified powder
particles having an interior portion containing an interior
composition, and an outer surface portion with an outer composition
different from the interior composition.
[0042] A further embodiment of the foregoing method, wherein the
interior composition is substantially identical to a composition of
the first powder.
[0043] A further embodiment of any of the foregoing methods,
wherein the outer composition is substantially identical to a
composition of the heated second powder.
[0044] A further embodiment of any of the foregoing methods,
wherein the outer composition includes at least some of the second
powder alloyed with a portion of the first powder.
[0045] A further embodiment of any of the foregoing methods,
wherein the first powder comprises a metal selected from a group
consisting of: nickel, titanium, chromium, aluminum, and alloys
thereof.
[0046] A further embodiment of any of the foregoing methods,
wherein the second powder comprises a second metallic material or a
precursor thereof.
[0047] A further embodiment of any of the foregoing methods,
wherein the second metallic material is an alloying element
compatible with the first metallic material.
[0048] A further embodiment of any of the foregoing methods,
wherein the second powder comprises a ceramic material or a
precursor thereof.
[0049] A further embodiment of any of the foregoing methods,
wherein the second material comprises a ceramic material selected
from a group consisting of: boron nitride, silicon carbide, silicon
nitride and combinations thereof.
[0050] A further embodiment of any of the foregoing methods,
further comprising: consolidating the modified powder into at least
part of a bulk material.
[0051] A further embodiment of any of the foregoing methods,
wherein the consolidating step comprises: disposing the combined
first powder and second powder onto a working surface of an
additive manufacturing apparatus; and operating an energy beam in a
linear manner so as consolidate the combined powders into at least
one layer of a bulk material.
[0052] A further embodiment of any of the foregoing methods,
wherein the consolidating step comprises: placing the combined
first powder and second powder into a feed chamber of a cold spray
apparatus; and operating the cold spray apparatus to form a coating
on a bulk material.
[0053] A method for operating an additive manufacturing apparatus
includes providing a metallic first powder material having a mean
diameter of more than about 500 nm to a working surface of the
additive manufacturing apparatus. A second powder material is added
to the working surface which has a mean diameter of less than about
100 nm. An energy beam is directed to apply energy to at least the
second powder material so as to selectively heat the second
particles. The first powder is combined with the heated second
powder to form a modified powder including modified powder
particles. The modified particles have an interior portion
containing an interior composition, and an outer surface portion
with an outer composition different from the interior
composition.
[0054] The method of the preceding paragraph can optionally
include, additionally and/or alternatively, any one or more of the
following features, configurations and/or additional
components:
[0055] A method for operating an additive manufacturing apparatus
according to an exemplary embodiment of this disclosure, among
other possible things includes providing a metallic first powder
material having a mean diameter of more than about 500 nm to a
working surface of the additive manufacturing apparatus; adding a
second powder material to the working surface, the second powder
material having a mean diameter of less than about 100 nm;
directing an energy beam to apply energy to at least the second
powder material so as to selectively heat the second particles; and
combining the first powder with the heated second powder to form a
modified powder including modified powder particles having an
interior portion containing an interior composition, and an outer
surface portion with an outer composition different from the
interior composition.
[0056] A further embodiment of the foregoing method, wherein the
metallic first powder comprises a metal selected from a group
consisting of: nickel, titanium, chromium, aluminum, and alloys
thereof.
[0057] A further embodiment of any of the foregoing methods,
wherein the second powder comprises a second metallic material or a
precursor thereof.
[0058] A further embodiment of any of the foregoing methods,
wherein the second powder comprises a ceramic material.
[0059] A further embodiment of any of the foregoing methods,
wherein the second material comprises a ceramic material selected
from a group consisting of: boron nitride, silicon carbide, silicon
nitride, and combinations thereof.
[0060] A method for manufacturing a bulk material includes
providing a metallic first powder having a plurality of first
particles with a first mean particle diameter. A second powder
added to the first powder has a plurality of second particles with
a second mean particle diameter less than the first mean particle
diameter. Energy is applied to at least the second powder so as to
selectively heat the second particles. The first powder is combined
with the heated second powder to form a modified powder including
modified powder particles. Modified powder particles have an
interior portion containing an interior composition, and an outer
surface portion with an outer composition different from the
interior composition. The modified powder particles are accelerated
through a cold spray apparatus, and are directed toward a
substrate.
[0061] The method of the preceding paragraph can optionally
include, additionally and/or alternatively, any one or more of the
following features, configurations and/or additional
components:
[0062] A method for forming at least part of a bulk material with a
cold spray apparatus according to an exemplary embodiment of this
disclosure, among other possible things includes providing a
metallic first powder having a plurality of first particles with a
first mean particle diameter; adding a second powder to the first
powder, the second powder having a plurality of second particles
with a second mean particle diameter less than the first mean
particle diameter; applying energy to at least the second powder so
as to selectively heat the second particles; combining the first
powder with the heated second powder to form a modified powder
including modified powder particles having an interior portion
containing an interior composition, and an outer surface portion
with an outer composition different from the interior composition;
accelerating the modified powder particles through the cold spray
apparatus; and directing the accelerated powder particles toward a
substrate.
[0063] A further embodiment of the foregoing method, wherein the
metallic first powder comprises a metal selected from a group
consisting of: nickel, titanium, chromium, aluminum, and alloys
thereof.
[0064] A further embodiment of any of the foregoing methods,
wherein the second powder comprises a second metallic material.
[0065] A further embodiment of any of the foregoing methods,
wherein the second metallic material comprises at least one
alloying composition compatible with the first metallic
material.
[0066] A further embodiment of any of the foregoing methods,
wherein the second powder comprises a ceramic material.
[0067] A further embodiment of any of the foregoing methods,
wherein the second material comprises a ceramic material selected
from a group consisting of: boron nitride, silicon carbide, silicon
nitride and combinations thereof.
[0068] Although the present invention has been described with
reference to preferred embodiments, workers skilled in the art will
recognize that changes may be made in form and detail without
departing from the spirit and scope of the invention.
* * * * *